Apparatus for color estimation.



J. W. Lawson. APPARATUS FOB OOLOB. ESTIMATION. APP'LIO'ATION FILED' HAY2, 1910'.

. i NVE/via@ ra/Mfrs Pzrnu co., WAJHINUNN, D. c.

UNITED STATES PATENT OFFICE.

JOSEPH WILLIAMS LOVIBOND, OF SALISBURY, ENGLAND.

APPARATUS FOR COLOR ESTIMATION.

To all whom t may concern.'

Be it known that I, JOSEPH l/VILLIAMS Lovinonn, a subject of the King ofGreat Britain, and resident of rlhe Pleasaunce, Lake, Salisbury, in thecounty of VVilts,

`lifngland, have invented certain new and useful Improvements inApparatus for Color Estimation, of which the following is aspecification.

rlhis invention relates to improvements in apparatus for use inestimating the intensity of colors, more especially apparatus of thekind which comprises a pair of sightingtubes whereof the one may containa sample of the object whose color is to be tested, while the other isadapted to receive a translucent screen or series of screens (exhibitinga standard tint or series of tints) through which a surface of standardluminosity is viewed; the quality and intensity of color in the samplebeing ascertained by varying the tints composing the screens until thequality and intensity of the colors seen through both tubes areidentical.

It sometimes happens that it is required to test the color of an objectof which no sample capable of being introduced into the instrument isavailable and which may therefore require to be observed 'in situ,s-innetimes while occupying an inaccessible position. Again, it may bedesirable to point the instrument in a direction which precludes theuse, within the instrument itself, of an artificial light (such as e. g.a standard candle), so that it becomes desirable to fix the standardlight externally of the instrument in a position where it is not liableto be affected by the movements of the latter. It has been foundmoreover, that the instrument possesses very high value when used forthe purpose of what may be called a chromo-pyrometer for the estimationof the temperatures of luminous bodies such as the interior of furnaces,it being possible by this means to ascertain and record with greatprecision temperatures of any height, however great, by the estimationof the color and light-intensity of the incandescent body or surface.But it is evident not only that the interior of all furnaces is quiteinaccessible7 but that it may be essential for the purpose of conductinga test that the line of vision toward t-he furnace should follow adirection widely different from that in which the standard light isviewed, inasl much as this light must obviously be exter- Specoaton ofLetters Patent.

Application led May 2, 1910.

Patented Mar. 2l, 19311.

serial no. 558,926.

nal to the furnace and may require to be mounted independently of theinstrument itself.

It is the objectof the present improvement to meet requirements such asthose mentioned above, and to this end the invention consists inproviding means whereby to enable objects external to the instrument tobe readily viewed, whatever their position relatively to the observer orwhatever the direction in which the latter may require to face or topoint the instrument.

According to the present invention either or both of the sighting-tubesof the instrument may be provided with anextension so attached to thebody of the instrument as to be capable of angular adjustment either inone direction or (preferably) in any direction within wide limits, areflector or reflectors being so mounted as to cause rays of light fromthe object toward which the eX- tension is directed to be projectedthrough the sighting-tube to the eye-piece.

In its simplest form the extension may consist of an elbow tube bent to(preferably) a right angle, the inner limb of the bent tube being fittedto rotate in an aperture in the objective or outer end of the instrumentopposite to the eye-piece, and .a plane reflector being mounted in theelbow so as to be adapted to receive and transmit to the eye-piece therays which pass from without through the outer limb of the eX-tension-tube. It is generally preferable, however, to provide one orboth of the sighting-tubes of the instrument with an eXtension-tubeconnected to the sighting-tube by means of a double or universal joint,means being provided for excluding stray rays of light at the joint whenthe direction of fleXure is changed, and a reflector or reflectors beingemployed at the joint for the purpose of transmitting to the eye-piecethose rays which enter the outer limb of the extension-tube.

In thel accompanying drawings, Figure 1 is a plan view partly insection, showing the improved instrument in the simpler form alreadymentioned, one of the sighting-tubes being provided with an extensionwhich is adjustable in one direction only; while Fig. 2 is a part axialsection of the sighting and extension tubes at their point of junction,drawn to a larger scale. Fig. 3 is a plan view, partly in section,showing an instrument each of whose sighting-tubes is provided with anextension which is adjustable in any directionwithin wide limits. Fig. 4isa detailed side elevation, partly in section, on the common plane ofthe axes of the sighting and extension tubes, showing one of thetube-joints of the instrument shown in Fig. 8; while Fig. 5 is a view ofthe same looking in a direction at right angles to that of Fig. 4, thetubes being extended in mutual alinement and certain parts beingremoved. Fig. V6 is a part section on line 66 of Fig. 4. Figs. 4 to 6are drawn to a larger scale than Figs. l and 3.

' lpa'rt from the improvements forming the subject of the presentinvention, what may be termed the typical form of the instrument, asindicated in Fig. 1, comprises a.

casing A divided by a longitudinal partition a into a pair of` laterallyjuxtaposed sighting-tubes B1, B? both of which are commanded from theeye-piece and by a single eye-hole in the form of a transverse slot Bprovided in the rear wall of the casing, the objective-ends of therespective sighting-tubes having apertures of equal areas. At or beyondthe end Vof one of the tubes (B2 in Fig. l), which may be distinguishedas the standard sighting-tube, is placed the source or medium ofillumina- Vtionconstituting the standard. If, as in the exampleillustrated, artificial light Vbe employed for the purpose vthis may beconstituted by a standard candle C so supported as to be adjustabletoward and from the eye-hole B. The illuminant may be such, or soplaced, as to be viewed directly or through a white translucent screenor screens, or by reflection from a surface of standard whiteness.Between the standardilluminant or reflecting surface andthe eye-hole B,the standard tube B2 is provided with means, as indicated at D2, 'forthe interposition in the line of sight of a variable series ofstandardized translucent color screens, While similar provision may bemade in the other Vor test sighting-tube- B1 for the interposition int-he line-of sight,

' Vasindicated at D1, of `such Astandardized translucent screens as itmay -be found necessary to employ for the purpose of (say) rreducing theluminosity of the object under observation.

The body A of the instrument Imay for convenience be mounted to turn asat E about a vertical axis carried vby atripod stand whereof the legskare indicated at c.

ln the improved form 'of the invention illustrated in Figs. 1 and2,'thetest sighting-tube B1, through which the externallysituated objectunder observation is viewed, is provided with van angularly :adjustableextension constituted by a tube F extending at anangle, preferably aright angle as in'- dicated, to the axis b-b of the tube 1B1`; Vtheinner portion of the'extension-tube F being bent elbow-wise so that theinner limb f1 thus formed extends in axial alinement with the tube B1itself. The limb f1 is so ointcd to the tube B1 as to be rotatable aboutthe common axis b-b of both, with the result that the tube F may beturned about said axis so as to command all objects lying within theplane of rotation of its own axis f-f. To enable the angular adjustmentthus effected to be maintained, the limb f1 of the extension-tube mayenter the tube B1 through a gland G (Fig. 2) which screws into a socketg on the casing A and is tapered and split so as to contract and gripthe limb f1 when the extension F has 'been turned so as to command theobject which it is desired to observe.

At the elbow, or point of intersection of the axes b-b and f-f, islixedly mounted a plane reflector lH whose surface lying in a planeperpendicular to the common plane'of said axes, makes equal angles withboth, so that rays from the object under observation, passing throughthe extensiontube F and falling upon the reflector H, will always betransmitted through the tube B1 to the eye-hole B.

The reflector H is preferably made removable for t-he purpose ofenabling it to be 'cleaned or repaired when necessary, and

may if desired be provided with means for permitting adjustment of itsposition after replacement.

It will be seen that by means of the combined angular adjustment of theextensiontube F about the axis Z)-Z), and of the casing A about thevertical axis E of the tripod stand of the instrument, the line of sightthrough the tubes B1 and F may be made to command any object, whateverits position, assuming that no obstacle to the view is interposed in thepath of the visual ray.

In the improved form of the instrument illustrated in Figs. 3 to 6, eachof thesighting-tubes B1 and B2 is provided with an angularly adjustableextension constituted by a pair of tubes F1, F2, whereof the inner tubevis jointed to the casing A so as to be rotatable about the common axisb4?) of B1 and F1, while the outer tube F2 is hinged to the tube F1 soas lto be adjustable, in the same plane therewith, through a wide anglewith reference to the tube F1 (in the example illustrated about 127g`degrees); with the result that, by moving the tube F2 angularly withreference to the tube F1 while the latter is turned about the axis [Q-Z), the line of sight represented by the axis f f of the tube F2 may bedirected so as to command vany object within the range of such compoundmovement.

At the point of intersection of the axes ZJ-b and f-f is mounted a planereflector H whose surface is automatically caused to so 'adjust itselfas, while remaining in a plane perpendicular to the common plane of saidaxes, to maintain equal angles with both axes whatever their angularposition relatively to one another, so that rays from the object underobservation, passing through the extension tube F2 and falling upon thereflector H, will always be transmitted through thel tube B1 to theoye-hole B. For this purpose, in the example illustrated, the reector His fixedly mounted in a carrier J to which both the tubes F1 and F2 arepivotally attached by means of a pair of trunnions X, X, whose commonaxis, which lies in the plane of the surface of the reflector H, alsoextends perpendicular to the common plane of the axes 6 6 and f-f,intersecting said plane at the point a2. To insure maintenance of equalangles between the surface of the reflector and the axes b--b and f-frespectively, the carrier J is provided with a rod K whose axisintersects the surface of the reflector' H perpendicularly at the point03,' this rod being itself caused to constantly bisect the angle betweenthe axes -b and f-f, by means of a pair of links L1 L2 of equal lengthwhich are pivotally attached on the one hand to the tubes F1 F2 atpoints Z1, Z2 equidistant from the point and on the other hand to oneanother at a common axis represented by a pair of trunnions Z providedon a collar L fitted to slide upon the rod K, whose axis is intersectedby that of the trunnions Z.

rlhe reflector H may be adjustably fixed in the carrier J, for whichpurpose, in the example illustrated, the reflector is made rectangularand supported at its corners by four springs M which concurrently pressit in the direction of the axis of the rod K,

the tendency of the reflector to move in said direction being restrainedby four adjustable screw-bolts N which pass through the carrier J andsprings M so that by tightening the nuts n of the bolts, the heads m ofthe latter will draw down the respective corners of the reflector inopposition to the springs M.

Accurate adjustment of the reflector H is obviously of great importance,and to enable it to be readily ascertained at any moment, the rod K may,as in the example illustrated, be made tubular and provided toward theinner end of its axis with an index-point whose image reflected from thesurface of the reflector H, should coincide with the index-point itselfwhen both are viewed from the outer end of the tube K. In Figs. 5 and 6,the index-point is shown as constituted by the sharpened extremity 0 ofa small setscrew O passed through the side of the tube K as far as theaxis of the latter', while the outer end of said tube is provided withan eye-piece P which is furnished with a removable plug p for preventingaccess of light to the reflector H when the adjustment described is notbeing made.

For the purpose of enabling the angular adjustment of the tube F2relatively to the tube F1 tobe maintained, the collar L may beinternally threaded to receive a tapered and split bush Q, alsothreaded, so that by screwing this bush into the collar L, the latterwill be clamped upon the rod (or tube) K. The angular adjustment of thetube F1 in its bearing in the tube B1 may be maintained by meanssubstantially similar to those already described with reference to thecorresponding adjustment in F l, or, as indicated in Fig. 4, by means ofa ring Q4 which screws over a split and externally tapered tube Q1 whichis fixed to the casing A and constitutes a bearing through which thetube F1 passes and wherein it is capable of being rotated.

It will be seen that by the use of angularly adjustable extension-tubesas last dcscribed for both sighting-tubes B1 and B2, the instrument as awhole is rendered independent of the nature and position both of thestandard illuminant and also of the object under observation, either orboth of which may even be situated toward the rear of the observer;while in the cas-e of the arrangement illustrated, any adjustment notobtainable by conjoint angular movement of the two extension-tubes F2may be obtained by concurrent rotation of the casing A about thevertical axis E.

R is a bag of fabric impervious to light (such as black velvet with thepile turned inward), which incloses the reflector H and the adjacentends of the tubes F1, F2 and K so as to exclude all stray rays from thereflector-while observations are being made.

The interior of the parts traversed by the rays from the object viewedwould be blackened as usual and fitted with stops adapted to interceptall except the sensibly parallel rays.

It is preferable to arrange the extension of any sighting-tube which isadapted toreceive the translucent screens, beyond or outside the latter,so that the adjustment of the extension-tube will not tend to disturbthe screens or interfere with their manipulation.

Inasmuch as every reflecting medium absorbs a portion of the light whichfalls upon .it and may also color the light transmitted by thereflector, it is necessary, in order that the lightk transmitted by theimproved instrument may be compared with existing standards, that theabsorption and colormodification due to each reflector employed shouldbe ascertained and standardized. Moreover, whereas on the one hand, inthe case of the fixed reflector employed in the reason that (the anglesof incidence upon i ir form ofapparatus illustrated in Fig. 1, ai glassmirror may be employed, for the and reflection from this mirror znevervarying) the degree Vof absorption and color modification due to thereflector is not liable' toalteration, on the other hand in the case ofthe movable reflector employed in the form of apparatus illustrated inFig. 3, the f kmirror lshould b-e of speculum (or other) l metal inorder that the changes in the angles of incidencel and reflection maynot result in alterations in the degree of `absorption andcolor-modifications.

Claims.

l. In apparatus for color estimation provided vvith a pair vof sighttubes, in combination; an extension tube at the end fof and set at anlangle to a sight tube and reflecting means at the junction of saidtubes,\substan tially as and for the purposedescribed.

2. In apparatus for color estimation pro vided With a pair of sighttubes, in combination, an extension tube at the end of andset at anangle to a sight tube and a .reflector at 4 `the unction of said tubessaidreflector mal;-

ing equal angles With each of said tubesand being perpendicular to theplane of said tubes, substantially as vand for the purposey described.

3. In apparatus for color estimation provided With a pair of sighttubes, in com--` bination'; an extension tube at the end of and set atan angle to a sight tube, means for rotating" said extension tube aboutthe aX-is Aof the sight tube, and a reflector at the junction of saidtubes for turning light received through the extension tube down thesight tube, substantially as and for the purpose described. I j

4. In apparatus for Acolor estimation provided With a pair of sighttubes, in :combination; an angularly adjustable extension tube at theend of a sight tube, a reflector at the junction of said vtubes forturning light 're- 'ceived through the extension tube down the sighttube, and means for adjusting the reflector :as the eXtension 'tube isadjusted` so as 5to maintain rsaid reflector in reflecting positionfwith`reference fto said tubes, substantially fas and for the purposedescribed.

5. In 4apparatus for color estimation provided vvith Vapair of sighttubes, in combination; an ,angularly adjustable extension tube at theend of a sight tube, a reflector at `the junctionof said tubes arrangedto turn light -received `through the Aextension tube down the sighttube, land means automatically actuated'as the angle-of 4the'extensiontube is changed to maintain said reflector 'in reflect- Iing position,substantially as and for the purpose described.

6.V In apparatus for color estimation provided With a pair of sighttubes, kin combinatin; an extension tube at the end of and set atanyangle with said tube, a reflector making equal angles with said Vtubesat the junction thereof, means for changing the angle between' saidtubes, and 'operative means betweeneach lof said tubes and the reflectorwhereby the aforesaid angles between tubes `and reflector varemaintained equal as the angle between the tubes is changed,substantially as and for the purpose de scribed.

' 7. In apparatus for color estimation yprovided Witli a pairof sighttubes, incombination.; an extension tube at the end of a sight tube, vareflector making equal angles With said tubes at the junction thereof, arod fixed to and 4perpendicular to the reflector, and a pair of linkspivoted together as to -one end and slidable upon said rod and havingtheir other `ends pivoted one 1to each of said tubes, substantially asand for the Apurpose described.

JOSEPH WILLIAMS LOVIBOND. Witnesses: 'HERBERT D. JAMESON,

RIPLEY WILSON.

Copies of this `patent may be obtained `'for ve cents each, Ybyaddressing lthe Commissioner of `Patents.

Washington, .D. C.

